code: def test_identity():
      gis = ImageSignature()
      sig = gis.generate_signature("test.jpg")
      dist = gis.normalized_distance(sig, sig)
      assert dist == 0.0
  
file_path: image-match/tests/test_goldberg.py
imports: import pytest
  from numpy import ndarray, array_equal
  from image_match.goldberg import ImageSignature, CorruptImageError
label_desc: Use image node_id 7 for calling a global function with example usage: test_identity() without return types